The chromosome of Pseudomonas putida KT2440 carries two clusters of genes, denoted ars1 and ars2, that are annotated as putative arsenic resistance operons. In this work, we present evidence that both operons encode functional arsenic‐response regulatory genes as well as arsenic extrusion systems that confer resistance to both arsenite [As(III)] and arsenate [As(V)]. Transcriptional fusions of P_ars1 and P_ars2 to lacZ revealed that expression of both operons was induced by arsenite and arsenate. We generated single mutants in ars1 and ars2, which showed lower resistance to arsenic than the wild‐type strain. A double ars1/ars2 was found to be highly sensitive to arsenic. Minimum inhibitory concentrations (MICs) for single mutants decreased two‐ to fourfold with respect to the parental strain, while in the double mutant the MIC decreased 128‐fold for arsenite and 32‐fold for arsenate. Bioinformatic analysis revealed that the ars2 resistance operon is part of the core genome of P. putida, while the ars1 operon appears to only occur in the KT2440 strain, suggesting that ars1 was acquired by horizontal gene transfer. The presence of ars1 in KT2440 may explain why it exhibits higher resistance to arsenic than other P. putida strains, which bear only the ars2 operon.

中文翻译：

---

恶臭假单胞菌KT2440中两个ar操纵子在砷耐受中的协同作用。

的染色体P假单胞菌恶臭假单胞菌 KT2440基因携带的两个集群，表示为ARS 1和ARS 2，被注解为推定的抗砷操纵子。在这项工作中，我们提供证据表明两个操纵子都编码功能性砷响应调节基因以及赋予对砷[As（III）]和砷酸盐[As（V）]均具有抗性的砷挤压系统。P _ars1和P _ars2与lacZ的转录融合表明，两个操纵子的表达均由亚砷酸盐和砷酸盐诱导。我们在ars 1和ars 2中生成了单个突变体，其对砷的抵抗力比野生型菌株低。发现双ars 1 / ars 2对砷高度敏感。相对于亲本菌株，单个突变体的最低抑菌浓度（MICs）降低了两倍至四倍，而在双突变体中，亚砷酸盐的MIC降低了128倍，砷酸盐降低了32倍。生物信息学分析表明，ars 2抵抗操纵子是P核心基因组的一部分。假单胞菌，而ars 1操纵子似乎只出现在KT2440菌株中，这表明ars 1是通过水平基因转移获得的。ARS的存在KT2440中的1可以解释为什么它比其他P具有更高的抗砷性。携带仅ars 2操纵子的putida毒株。